vmtui 0.9.5.dev6

A text user interface (TUI) to control virtual machines on a per user basis

VMTUI

a text user interface to control libvirt VMs on a per user basis.

libvirt polkit configuration

VMTUI is intended as a simple interface to allow unprivileged user accounts to control (i.e. (re)start, shutdown, install) their personal virtual machines. To make use of this, libvirt must be configured to use polkit. The package provides a helper script gen_libvirt_polkit_acl that allows the generation of an ACL policy based on a yaml database.

The libvirtd.conf file must be modified src and virtqemud.conf as well:

/etc/libvirt/libvirtd.conf and /etc/libvirt/virtqemud.conf:

access_drivers = [ "polkit" ]

In this example, a user account must belong to the adm_vmhost group to get full priviliges. User accounts with personal VMs must belong to the user_vm group.

/etc/polkit-1/rules.d/100-libvirt-acl.rules:

polkit.addRule(function(action, subject) {
    if (
        subject.isInGroup("adm_vmhost") ||

        false // makes generation easier
       ) {
        if (action.id == "org.libvirt.unix.manage" || action.id.startsWith("org.libvirt.api")) {
            return polkit.Result.YES;
        }

        } else if ( subject.isInGroup("user_vm") ) {
            if (action.id == "org.libvirt.unix.manage" || action.id.startsWith("org.libvirt.api.connect")) {
                return polkit.Result.YES;
            } else if (action.id.startsWith("org.libvirt.api.domain") && action.lookup("connect_driver")=="QEMU") {
                var dom = action.lookup("domain_name");
                if((subject.user == "alice" && dom == "rocky9-2") ||
                   (subject.user == "bob" && dom == "rocky9-3") || // these are the "entry types that must be read from a file, either to grant access to a user or a group
                   false // makes generation easier
                ) {
                    return polkit.Result.YES;
                    } else {
                    return polkit.Result.NO;
                }
            } else if ( action.id.startsWith("org.libvirt.api.network") ) {
                if ( action.id.endsWith("getattr") ||
                     action.id.endsWith("read") ||
                     action.id.endsWith("create")
                    ) {
                    return polkit.Result.YES;
                } else {
                    return polkit.Result.NO;
                }
            }
    }
        return polkit.Result.NO;
}
);

The example grants the user alice access to the domain rocky9-2, while bob is allowed to manage rocky9-3.

To simplify the generation of the polkit ACL use the s script and provide a user_acl.yaml:

libvirt_acl:
  admin_groups: # configure groups that have full access
    - adm_vmhost
  domains: # domain specific ACL
    rocky9: # grant users alice and bob and members of the group mod_vmhost access to 'rocky9''
      users:
        - alice
        - bob
      groups:
        - mod_vmhost
    rocky9-2: # grant alice access to rocky9-2 
      users:
        - alice
    rocky9-3: # grant bob access to rocky9-3
      users:
        - bob

To generate the ACL (as root):

gen_libvirt_polkit_acl --acl /etc/libvirt_acl.yaml 

It might be necessary to restart libvirt and polkit.

systemctl restart polkit # usually automatically reloads files
systemctl restart libvirtd

SSH configuration for vmtui

You can limit ssh access to vmtui with the following configuration (limits members of the user_vm group to vmtui). It is recommended to use a virtual environment (here /opt/vmtui).

/etc/ssh/sshd_config.d/10-vmtui-conf

Match Group user_vm
    ForceCommand /opt/vmtui/bin/vmtui